Since the arrival of the picture information age, there has been demand for personalized, space-saving display devices. As a result, a variety of flat display devices, including thin film transistor-liquid crystal displays (TFT-LCD), plasma display panels (PDP), electro-luminescence devices (EL), and the like, have been developed, as a substitute for cathode-ray tubes (CRTs). The TFT-LCD is the main stream of the flat display device field and is based on a combination of a semiconductor technology and a liquid crystal technology utilizing optical properties of liquid crystals whose molecular arrangement varies as an electrical field is applied thereto.
The organic layer pattern that is widely used in manufacturing TFT-LCDs functions as a passivation film for achieving planarization of a TFT structure. In addition, the organic layer is used in forming an organic layer pattern functioning as an insulating layer for minimizing parasitic capacitance between each of pixel electrodes and data lines. With the increasing demand for large-scale TFT-LCD panels, the trend is to use large-scale substrates. Accordingly, development of a new photoresist composition for organic layer exhibiting coating uniformity suitable to form a large-scale substrate is highly demanded. As used herein, “coating uniformity” refers to uniformity in the thickness of photoresist composition for organic layer coated on the substrate, which exerts effects on an aperture ratio, resolution, and line width of a circuit. For example, a difference in reflectivity, which is caused due to a negligible difference in the thickness of organic layer, may cause a defect to the organic layer, which ultimately results in a defective TFT-LCD. In order to overcome this problem, the aperture ratio of the organic organic layer using benzocyclobutyne (BCB) may be increase. However, the cost ineffectiveness of this method makes it highly undesirable.
Therefore, development of a photoresist composition for an organic layer which does not result in defects such as stains or spots generated on an organic layer pattern remaining in a TFT-LCD after being coated and patterned is highly desirable. In addition, a photoresist composition for organic layer that can be minimally coated to the thickness required for attaining of increased durability during subsequent steps and ultimately reducing the manufacturing cost of the TFT-LCD is desirable.